Patent Application
20070253750
For a more complete understanding of the invention and the advantages thereof, reference is now made to the following description taken in conjunction with the accompanying drawings.
At least the following matters will be made clear by the description in the present specification and the accompanying drawings.
A layer-thickness restriction member, including:
an abutting surface that is for abutting against a developer-bearing body in order to restrict a layer thickness of developer borne by the developer-bearing body; and
a flash that is located on a side close to a non-abutting surface that is located on an opposite side from the abutting surface in a thickness direction of the layer-thickness restriction member.
If the flash of the layer-thickness restriction member is located on the side close to the non-abutting surface that is located on the opposite side from the abutting surface in the thickness direction, the flash is unlikely to affect the layer thickness of the developer, so that the layer thickness of the developer can be restricted evenly.
In addition, a base of the flash may be located between the abutting surface and the non-abutting surface in the thickness direction; and the flash may include a flash whose edge is located on a side close to the abutting surface with respect to the base in the thickness direction, and a flash whose edge is located on a side close to the non-abutting surface with respect to the base in the thickness direction.
If the flash includes the flash whose edge is located on the side close to the abutting surface with respect to the base in the thickness direction, and the flash whose edge is located on the side close to the non-abutting surface with respect to the base, the flashes are located unevenly in the thickness direction and this increases a possibility that the layer thickness of the developer becomes unevenly. Therefore, an effect generated by positioning the flash on the side close to the non-abutting surface in the thickness direction, that is, an effect that the layer thickness of the developer is restricted evenly, is achieved more effectively.
In addition, the layer-thickness restriction member may include a first portion that includes the abutting surface and that is located on a one-end side in the thickness direction, and a second portion that includes the non-abutting surface and that is located on an other-end side in the thickness direction and is connected to the first portion; and a length of the first portion in a transverse direction of the layer-thickness restriction member may be larger than a length of the second portion in the transverse direction.
In addition, a base of the flash may be located on an edge of a surface, of the first portion, that is located on the opposite side from the abutting surface; and a length of the first portion in the thickness direction may be larger than a length of the second portion in the thickness direction.
In the case where the base of the flash is located on the edge of the surface, of the first portion, that is located on the opposite side from the abutting surface, if the length of the first portion in the thickness direction is larger than the length of the second portion in thickness direction, it is possible to position the flash on the side close to the non-abutting surface even in a simple configuration.
In addition, a ten-point average height of irregularities of the abutting surface may be smaller than a ten-point average height of irregularities of the non-abutting surface.
In such a case, projections and depressions of the abutting surface are small, and this enables to more evenly restrict the layer thickness of the developer borne by the developer-bearing body.
In addition, a first curve may be formed on an edge of the abutting surface; a second curve may be formed on an edge of the non-abutting surface; and a radius of curvature of the first curve may be smaller than a radius of curvature of the second curve.
If the radius of curvature of the first curve is smaller than the radius of curvature of the second curve, the edge of the abutting surface on which the first curve is formed can be sharpened. In this case, it is possible to more effectively bring the developer between the abutting surface and the developer-bearing body.
In addition, the layer-thickness restriction member may be made of thermoplastic elastomer.
In such a case, a layer-thickness restriction member with great accuracy of thickness is easy to be molded.
A layer-thickness restriction member, including:
an abutting surface that is for abutting against a developer-bearing body in order to restrict a layer thickness of developer borne by the developer-bearing body;
a flash that is located on a side close to a non-abutting surface that is located on an opposite side from the abutting surface in a thickness direction of the layer-thickness restriction member;
wherein,
a base of the flash is located between the abutting surface and the non-abutting surface in the thickness direction;
the flash includes
the layer-thickness restriction member includes
a length of the first portion in a transverse direction of the layer-thickness restriction member is larger than a length of the second portion in the transverse direction;
the base of the flash is located on an edge of a surface, of the first portion, that is located the opposite side from the abutting surface;
a length of the first portion in the thickness direction is larger than a length of the second portion in the thickness direction;
a ten-point average height of irregularities of the abutting surface is smaller than a ten-point average height of irregularities of the non-abutting surface;
a first curve is formed on an edge of the abutting surface;
a second curve is formed on an edge of the non-abutting surface;
a radius of curvature of the first curve is smaller than a radius of curvature of the second curve; and
the layer-thickness restriction member is made of thermoplastic elastomer.
With this layer-thickness restriction member, an effect that the layer thickness of the developer is restricted evenly is achieved most effectively.
A developing device, including:
a developer-bearing body that is for bearing developer; and
a layer-thickness restriction member that includes an abutting surface that is for abutting against the developer-bearing body in order to restrict a layer thickness of developer borne by the developer-bearing body, and that includes a flash that is located on a side close to a non-abutting surface that is located on an opposite side from the abutting surface in a thickness direction of the layer-thickness restriction member.
With this developing device, the layer thickness of the developer borne by the developer-bearing body can be restricted evenly by the layer-thickness restriction member.
In addition, the developer-bearing body may be a developer-bearing roller that is rotatable about a central axis; a longitudinal direction of the layer-thickness restriction member may be along an axial direction of the developer-bearing body; a base of the flash may be located between the abutting surface and the non-abutting surface in the thickness direction; the flash may include a flash whose edge is located on a side close to the abutting surface with respect to the base in the thickness direction, and a flash whose edge is located on a side close to the non-abutting surface with respect to the base in the thickness direction; and the flash may be located from a longitudinal-direction one end to a longitudinal-direction other end of the layer-thickness restriction member.
If the flash is located from the longitudinal-direction one end to the longitudinal-direction other end, an effect generated by positioning the flash on the side close to the non-abutting surface in the thickness direction, that is, an effect that the layer thickness of the developer is restricted evenly, is achieved more effectively.
In addition, the developing device may include a supporting member to which the non-abutting surface adheres and that is for supporting the layer-thickness restriction member; and none of the flashes may be in contact with the supporting member.
If none of the flashes is in contact with the supporting member, the layer-thickness restriction member is appropriately supported by the supporting member. Therefore, the layer-thickness restriction member can properly abut against the developer-bearing body.
A method for manufacturing a restriction blade, including:
molding by injection molding an abutting member, made of thermoplastic elastomer, of a restriction blade that is for restricting, by abutting against a developer-bearing body, a layer thickness of developer borne by the developer-bearing body
making the adhering surface of the abutting member that is molded by injection molding and a supporting member that is included in the restriction blade and that is for supporting the abutting member adhere to each other.
In the case where molding by injection molding the abutting member, by injecting the thermoplastic elastomer into the mold wherein the first mold and the second mold overlap such that the boundary surface between the first mold and the second mold is located between these two molds in the direction from the abutting-surface forming section toward the adhering-surface forming section, the flash is located away from the adhering surface even if the flash is created on a section of the boundary surface when molding by injection molding. Therefore, when making the adhering surface and the supporting member adhere to each other, the flash is unlikely to contact the supporting member. Accordingly, the supporting member properly adheres to the adhering surface. This increases the precision of the manufactured restriction blade.
In addition, the mold may be a metal mold; the first mold may have a first depression whose bottom surface is the abutting-surface forming section; the second mold may have a second depression whose bottom surface is the adhering-surface forming section; when the first mold and the second mold overlap, the boundary surface may be located between the first depression and the second depression in the direction from the abutting-surface forming section toward the adhering-surface forming section; and when the abutting member is molded by injection molding, the abutting member may be molded by injection-molding by injecting the thermoplastic elastomer into the first depression and the second depression.
In addition, a depth of the first depression may be larger than a depth of the second depression.
The restriction blade restricts the layer thickness of the developer borne by the developer-bearing body, but there is a possibility in which the layer thickness of the developer is restricted unevenly if the flash of the abutting member that is molded by injection molding is located on the side close to the abutting surface in the thickness direction. On the other hand, if the depth of the first depression is larger than the depth of the second depression, the flash that is created between the first depression and the second depression in injection molding is located on the side close to the adhering surface, among the abutting surface and the adhering surface, in the thickness direction. As a result thereof, it is possible to prevent the layer thickness of the developer borne by the developer-bearing body from being restricted unevenly.
In addition, a width of the first depression in a transverse direction may be larger than a width of the second depression in the transverse direction.
There are cases in which the first mold and the second mold overlap with their positions relative to each other being shifted when the mold is closed. In such a case, if the width of the first depression in the transverse direction is the same as the width of the second depression in the transverse direction, a position at which the flash is created in injection molding is likely to vary when the first mold and the second mold overlap with their relative positions being shifted. On the other hand, if the width of the first depression in the transverse direction is larger than the width of the second depression in the transverse direction, the position at which the flash is created does not vary even when the first mold and the second mold overlap with their positions relative to each other being shifted.
In addition, a shape of the abutting member may be adjusted by cutting both end sections of the abutting member that is molded by injection molding in the longitudinal direction; and when making the adhering surface of the abutting member and the supporting member adhere to each other, the adhering surface of the abutting member whose shape is adjusted and the supporting member may adhere to each other.
In such a case, the flash is not located in the transverse direction of the abutting member. Therefore, the adhering surface of the abutting member that is molded by injection molding and the supporting member can adhere to each other more properly.
In addition, when making the adhering surface of the abutting member and the supporting member adhere to each other, the adhering surface of the abutting member and the supporting member may adhere to each other such that a flash of the abutting member that is molded by injection molding is not in contact with the supporting member.
If the adhering surface of the abutting member and the supporting member adhere to each other such that the flash of the abutting member that is molded by injection molding is not in contact with the supporting member, the adhering surface and the supporting member can adhere to each other more properly.
In addition, when making the adhering surface of the abutting member and the supporting member adhere to each other, the supporting member may be held by a first jig; the abutting member may be held by a second jig such that the flash of the abutting member that is molded by injection molding is not in contact with the second jig; and the adhering surface and the supporting member may adhere to each other in such a manner as to move the first jig holding the supporting member relative to the second jig holding the abutting member so as to become close to each other such that the adhering surface of the abutting member comes in contact with the supporting member.
If the abutting member is held by the second jig such that the flash of the abutting member that is molded by injection molding is not in contact with the second jig, the flash is not sandwiched between the abutting member and the second jig. Therefore, the abutting member is positioned properly with respect to the second jig.
A blade-forming mold, including:
a first mold that includes an abutting-surface forming section for forming an abutting surface of an abutting member, made of thermoplastic elastomer, of a restriction blade that is for restricting, by abutting against a developer-bearing body, a layer thickness of developer borne by the developer-bearing body; and
a second mold that is movable relative to the first mold, and that includes an adhering-surface forming section for forming an adhering surface, of the abutting member, that is located on a side opposite the abutting surface in a thickness direction of the abutting member and adheres to a supporting member that is included in the restriction blade and that is for supporting the abutting member;
With this blade-forming mold, it is possible to manufacture the abutting member whose adhering surface adheres to the supporting member properly.
As mentioned above, a restriction blade is provided in a developing device included in an image forming apparatus, and restricts a layer thickness of toner, which is an example of developer borne by a developing roller, by abutting the developing roller, which is an example of a developer-bearing body.
In this section, an overview of the image forming apparatus is initially described for an example of a laser beam printer (hereinafter referred to as a printer), and thereafter a developing device and a restriction blade are described in sequence.
First, examples of configuration and operation of a printer 10 are described with reference to
As shown in
The photoconductor 20 has a cylindrical conductive base and a photoconductive layer formed on an outer peripheral surface of the base. The photoconductor 20 is rotatable about its central axis, and rotates clockwise in this embodiment, as indicated by the arrow in
The charging unit 30 is a device for charging the photoconductor 20. The exposing unit 40 is a device that forms a latent image on the charged photoconductor 20 by radiating laser beams thereon. The exposing unit 40 has a semiconductor laser, a polygon mirror, an F-S lens, and the like, and radiates modulated laser beams onto the charged photoconductor 20 according to image information (image signals) that has been inputted by a not-shown host computer, such as a personal computer and a word processor.
YMCK developing unit 50 is a device for developing a latent image that is formed on the photoconductor 20, using toners contained in the developing device, that is, a black (K) toner contained in a black developing device 51, a magenta (M) toner contained in a magenta developing device 52, a cyan (C) toner contained in a cyan developing device 53, and a yellow (Y) toner contained in a yellow developing device 54.
The YMCK developing unit 50 rotates with the four developing devices 51, 52, 53, 54 being attached thereto so that it enables to move positions of the four developing devices 51, 52, 53, 54. More specifically, the YMCK developing unit 50 holds the four developing devices 51, 52, 53, 54 with four holding sections 55a, 55b, 55c, 55d, and the four developing devices 51, 52, 53, 54 are rotatable about a central axis 50a while keeping their respective positions relatively. Every time an image forming process for one page is finished, the four developing devices 51, 52, 53, 54 selectively opposes the photoconductor 20, and successively develops a latent image formed on the photoconductor 20, using toners contained in each of the developing devices 51, 52, 53, 54. Note that, the above-mentioned four developing devices 51, 52, 53, 54 are attachable to and detachable from the respective holding sections of the YMCK developing unit 50. Details of each developing device will be described later.
The first transfer unit 60 is a device for transferring a single-color toner image formed on the photoconductor 20, onto the intermediate transfer body 70. When toners of four colors are successively transferred in a superposed manner, a full-color toner image is formed on the intermediate transfer body 70.
The intermediate transfer body 70 is an endless belt that is made by providing a tin layer by vapor deposition on a surface of a PET film and further applying and laminating semiconducting coating on the outer layer thereof. The intermediate transfer body 70 is driven and rotated at the approximately same circumferential speed as the photoconductor 20.
The second transfer unit 80 is a device for transferring the single-color toner image or the full-color toner image formed on the intermediate transfer body 70, onto a medium, such as paper, film, and cloth.
The fusing unit 90 is a device for fusing, onto the medium, the single-color toner image or the full-color toner image that have been each transferred onto the medium, to make the image into a permanent image.
The cleaning unit 75 is provided between the first transfer unit 60 and the charging unit 30, and includes a cleaning blade 76 that is for cleaning the photoconductor 20 by abutting against the photoconductor 20 and scraping off toner that remains on the photoconductor 20. The cleaning unit 75 is a device for removing the toner that remains on the photoconductor 20, by scraping off toner with the cleaning blade 76 after the toner image has been transferred onto the intermediate transfer body 70 by the first transfer unit 60.
The control unit 100 is configured by a main controller 101 and a unit controller 102, as shown in
More specifically, the main controller 101 of the control unit 100 is connected to the host computer via an interface 112, and is furnished with an image memory 113 for storing image signals inputted by the host computer. The unit controller 102 is electrically connected to the units in the body of the apparatus (the charging unit 30, the exposing unit 40, the YMCK developing unit 50, the first transfer unit 60, the cleaning unit 75, the second transfer unit 80, the fusing unit 90, and the displaying unit 95). The unit controller 102 detects states of the units by receiving signals from sensors provided in these units, and controls these units based on signals inputted by the main controller 101.
Next, operations of the printer 10 having the above-mentioned configuration are described.
When image signals and control signals are inputted from the not-shown host computer to the main controller 101 of the printer 10 via the interface (I/F)112, the photoconductor 20, the developing roller, and the intermediate transfer body 70 rotate under control of the unit controller 102 according to instructions from the main controller 101. While rotating, the photoconductor 20 is successively charged by the charging unit 30 at a charging position.
With rotation of the photoconductor 20, the charged area of the photoconductor 20 reaches an exposing position. A latent image that corresponds to image information for a first color, for example yellow Y, is formed in the area by the exposing unit 40. Further, in the YMCK developing unit 50, the yellow developing device 54 containing the yellow (Y) toner is located at a developing position that opposes the photoconductor 20.
With rotation of the photoconductor 20, the latent image formed on the photoconductor 20 reaches the developing position, and is developed by the yellow developing device 54 with the yellow toner. As a result thereof, a yellow toner image is formed on the photoconductor 20.
With rotation of the photoconductor 20, the yellow toner image formed on the photoconductor 20 reaches a first transfer position, and is transferred onto the intermediate transfer body 70 by the first transfer unit 60. At this stage, a first transfer voltage, which is in an opposite polarity to the polarity to which the toner is charged is applied to the first transfer unit 60. Note that, during this process, the photoconductor 20 and the intermediate transfer body 70 are placed in contact with each other and the second transfer unit 80 is separated from the intermediate transfer body 70.
By performing successively the above-mentioned process for each of the developing devices associating with a second color, a third color, and a fourth color respectively, toner images in the respective four colors associated with the image signals are transferred onto the intermediate transfer body 70 in a superposed manner. As a result thereof, a full-color toner image is formed on the intermediate transfer body 70.
With rotation of the intermediate transfer body 70, the full-color toner image formed on the intermediate transfer body 70 reaches a second transfer position, and is transferred onto a medium by the second transfer unit 80. Note that the medium is transported from the paper supply tray 92 to the second transfer unit 80 via a paper supply roller 94 and resisting rollers 96. Besides, during the transfer operation, the second transfer unit 80 is pressed against the intermediate transfer body 70 and a second transfer voltage is applied to the second transfer unit 80.
The full-color toner image transferred onto the medium is heated and pressurized by the fusing unit 90, and is fused to the medium.
On the other hand, after the photoconductor 20 has passed the first transfer position, toner adhering to a surface of the photoconductor 20 is scraped off by the cleaning blade 76 that is provided in the cleaning unit 75, and the photoconductor 20 is prepared for charging that is for formation of a next latent image. The scraped toner T is collected by a residual toner collector included in the cleaning unit 75.
Next, examples of a configuration and operations of the developing device are described with reference to
The YMCK developing unit 50 is furnished with the black developing device 51 containing the black (K) toner, the magenta developing device 52 containing the magenta (M) toner, the cyan developing device 53 containing the cyan (C) toner, and the yellow developing device 54 containing the yellow (Y) toner. However, only the yellow developing device 54 is described below, because the configuration of each developing device is same.
The yellow developing device 54 includes the developing roller 510, an upper sealing member 520, a toner containing body 530, a housing 540, a toner supply roller 550, a restriction blade 560, and the like.
The developing roller 510 bears toner T to transport it to the developing position that opposes the photoconductor 20. The developing roller 510 is made of aluminum, stainless steel, iron, etc. and is nickel-plated, chrome-plated, or the like as necessary. Besides, as shown in
Further, when the yellow developing device 54 opposes the photoconductor 20, a gap exists between the developing roller 510 and the photoconductor 20. In other words, the yellow developing device 54 develops a latent image formed on the photoconductor 20 without contacting. Note that, when developing the latent image formed on the photoconductor 20, alternating electric field is generated between the developing roller 510 and the photoconductor 20.
The upper sealing member 520 prevents toner T in the yellow developing device 54 from spilling outside, and collects, into the developing device, toner T that has passed through the developing position and is on the developing roller 510, without scraping off the toner. The upper sealing member 520 is a seal made of polyethylene film, etc. The upper sealing member 520 is supported by an upper-seal supporting metal plate 522, and is mounted on the housing 540 via the upper-seal supporting metal plate 522. Besides, an upper-seal urging member 524 made of Moltoprene, etc. is provided on the upper sealing member 520 on a side opposite from a side close to the developing roller 510. The upper sealing member 520 is pressed against the developing roller 510 by elastic force of the upper-seal urging member 524. Note that an abutting position at which the upper sealing member 520 abuts against the developing roller 510 is located above the central axis of the developing roller 510.
The housing 540 is manufactured by welding together a plurality of housing sections that are integrally molded: a housing upper section 542 and a housing lower section 544. In the housing 540, the toner containing body 530 for containing toner T is formed. The toner containing body 530 is separated into two toner containers, namely, a first toner container 530a and a second toner container 530b, by a partitioning wall 545 which protrudes inwardly from an inner wall (to the up-and-down direction in
Therefore, in this embodiment, the toner containing body 530 is not furnished with a stirring member, but it is possible to provide a stirring member for stirring toner T that is contained in the toner containing body 530. Further, as shown in
The toner supply roller 550 is provided to the above-mentioned first toner container 530a. The toner supply roller 550 supplies to the developing roller 510 toner T contained in the first toner container 530a, as well as scrapes off, from the developing roller 510, toner T that remains on the developing roller 510 after development. The toner supply roller 550 is made of polyurethane foam, etc., and abuts against the developing roller 510 while being deformed elastically. The toner supply roller 550 is located in the lower section of the first toner container 530a, and toner T contained in the first toner container 530a is supplied to the developing roller 510 by the toner supply roller 550 at the lower section of the first toner container 530a. The toner supply roller 550 is rotatable about its central axis, and the central axis is located below the central axis of rotation of the developing roller 510. Further, the toner supply roller 550 rotates in a direction (clockwise in
The restriction blade 560 restricts a layer thickness of toner T borne by the developing roller 510, and also charges electrically toner T borne by the developing roller 510. The restriction blade 560 includes a rubber section 561 serving as an example of a layer-thickness restriction member that is for restricting a layer thickness of toner borne by the developing roller 510, and a rubber-supporting section 566 serving as an example of a supporting member that is for supporting the rubber section 561. Note that the configuration of the restriction blade 560 is described later in detail.
In the yellow developing device 54 constructed as mentioned above, the toner supply roller 550 supplies, to the developing roller 510, toner T contained in the toner containing body 530. With rotation of the developing roller 510, the toner T supplied to the developing roller 510 reaches an abutting position of the restriction blade 560; on passing through the abutting position, a layer thickness is restricted and the toner T is charged electrically. With further rotation of the developing roller 510, the charged toner T which is on the developing roller 510 and whose layer thickness is restricted reaches the developing position that opposes the photoconductor 20, and is used at the developing position in development of a latent image formed on the photoconductor 20 under alternating electric field. The toner T that is on the developing roller 510 and that has passed through the developing position with further rotation of the developing roller 510 passes through the upper sealing member 520, and the toner T is collected into the developing device without being scraped off by the upper sealing member 520. Furthermore, toner T that still remains on the developing roller 510 can be scraped off by the toner supply roller 550.
Next, a configuration example of the restriction blade 560 is described with reference to
The restriction blade 560 includes the rubber section 561 and the rubber-supporting section 566, and is provided such that the restriction blade 560 is along the developing roller 510 from one end side to the other end side in an axial direction of the developing roller 510. The restriction blade 560 restricts a layer thickness of toner T borne by the developing roller 510 by abutting against the developing roller 510, and also charges electrically the toner T borne by the developing roller 510.
The rubber section 561 is an abutting member that abuts against the developing roller 510 at an abutting surface 562a, and is for restricting a layer thickness of toner borne by the developing roller 510. The rubber section 561 abuts against the developing roller 510 such that the longitudinal direction of the rubber section 561 is along the axial direction of the developing roller 510. Besides, an adhering surface 563a of the rubber section 561, which is an example of a non-abutting surface located an opposite side from the abutting surface 562a in the thickness direction, adheres to the rubber-supporting section 566 with a double-sided adhesive tape 568 (
The rubber section 561 in this embodiment is made of thermoplastic elastomer (specifically, ether-based thermoplastic elastomer) (note that the rubber section 561 is made of thermoplastic elastomer, and strictly speaking the thermoplastic elastomer is different from rubber. However, in this example, the member indicated by the numerical reference 561 is referred to as the rubber section 561 for the sake of convenience).
Further, as shown in
Here, the long-side section 562 includes four surfaces that are along the longitudinal direction of the rubber section 561, namely, the above-mentioned abutting surface 562a, a front surface 562b that is located on a front end of the restriction blade 560 in the transverse direction, a rear surface 562c that is located on an opposite side from the front surface 562b, and an end surface 562d that is located on the opposite side from the abutting surface 562a. The short-side section 563 includes three surfaces that are along the longitudinal direction, namely, the above-mentioned adhering surface 563a, an end surface 563b that is located on a front end of the restriction blade 560 in the transverse direction, and an end surface 563c that is located on an opposite side from the end surface 563b.
As shown in
By the way, the rubber section 561 is a molded article that is molded by injection molding (to be described in detail later). On this rubber section 561 that is molded by injection molding, a flash, which is an unnecessary section, is created. Also, in this embodiment, on the developing devices 51, 52, 53, 54 that are constructed with the rubber section 561 being used as a component, some of flashes 564 remains, as shown in
Here, the flash 564 is described in detail. As shown in
The rubber-supporting section 566 is a thin metal plate that is made of phosphor bronze, stainless steel, etc. and that has a spring-like characteristic. The rubber-supporting section 566 has the rubber section 561 that adheres thereto with the double-sided adhesive tape 568 existing between the adhering surface 563a of the rubber section 561 and an adhering surface 566a of the rubber-supporting section 566, the adhering surface 566a adhering to the rubber section 561 (
Here, the rubber section 561 is pressed against the developing roller 510 by elastic force that is due to bending of the rubber-supporting section 566. Further, the blade back member 570 prevents toner T from entering between the rubber-supporting section 566 and the housing 540, and stabilizes elastic force that is due to bending of the rubber-supporting section 566. In addition thereto, the blade back member 570 presses the rubber section 561 against the developing roller 510 by urging the rubber section 561 from the back of the rubber section 561 toward the developing roller 510. Accordingly, the blade back member 570 makes the rubber section 561 abut more evenly against the developing roller 510.
An end, of the restriction blade 560, that is located on an opposite side from an end supported by the blade-supporting metal plate 567, that is, an edge (a one end of the abutting surface 562a in the transverse direction of the rubber section 561) is not in contact with the developing roller 510, as shown in
Here, a method for manufacturing the restriction blade 560 according to the first embodiment is described with reference to
Note that the left diagram of
First, the rubber section 561 of the restriction blade 560 is molded by injection-molding with an injection molding apparatus (an apparatus including the injection molding machine 252 and the mold 202, which is an example of a blade-forming mold (which is also merely referred to as a mold), is referred to as an injection molding apparatus in this embodiment) (step S102). More specifically, the rubber section 561 is molded by injection molding by injecting molten thermoplastic elastomer into the mold 202 from the injection molding machine 252 shown in
The thermoplastic elastomer is loaded into a hopper section 252a of the injection molding machine 252, and the loaded thermoplastic elastomer is heated and becomes molten in an injection barrel 252b. Then, the thermoplastic elastomer that is heated and becomes molten is injected into the mold 202 that is mounted on a mold-mounting section 252c of the injection molding machine 252. The thermoplastic elastomer that is injected into the mold 202 passes through a sprue 212 which is an opening for receiving of the thermoplastic elastomer injected by the injection molding machine 252, passes through a runner 214 which is a channel for leading the thermoplastic elastomer from the sprue to a gate, and passes through the gate 216 which is an entrance of a cavity 218. And, the thermoplastic elastomer fills the cavity 218 in the mold 202. A temperature of the mold 202 is kept at a temperature lower than a temperature of the thermoplastic elastomer, and the thermoplastic elastomer in the mold 202 is cooled by the mold 202 so that the rubber section 561 is molded.
Here, the structure of the above-mentioned mold 202 and a shape of the rubber section 561 that is molded by the mold 202 are described with reference to
The mold 202 includes two mold portions: a stationary mold portion 204 that is an example of a first mold that includes an abutting-surface forming section for forming the abutting surface 562a, and a movable mold portion 206 that is an example of a second mold that includes an adhering-surface forming section for forming the adhering surface 563a and that is movable relative to the stationary mold portion 204. As shown in
Besides, the mold 202 is furnished with the sprue 212, the runner 214, the gate 216, and the cavity 218, as mentioned above.
The sprue 212 is mainly provided in the movable mold portion 206 as shown in
The runner 214 is provided in the stationary mold portion 204, and includes a first channel 214a that is adjacent to the sprue 212, a second channel 214b that is adjacent to the first channel 214a, and a third channel 214c that is adjacent to the second channel 214b and reaches the gate 216. As shown in the left diagram of
As shown in the left diagram of
As shown in the left diagram of
As shown in
For the purpose of molding the rubber section 561 shown in
In a state in which the stationary mold portion 204 and the movable mold portion 206 that are both configured as mentioned above overlap (a state in which the mold 202 is closed), the thermoplastic elastomer is injected into the stationary-mold recess 205 and the movable-mold recess 207, and the rubber section 561 is molded by injection-molding. At this stage, when the stationary mold portion 204 and the movable mold portion 206 overlap, the boundary surface 221 between the stationary mold portion 204 and the movable mold portion 206 is located between the abutting-surface forming section 205a and the adhering-surface forming section 207a (between the stationary-mold recess 205 and the movable-mold recess 207) in a direction from the abutting-surface forming section 205a toward the adhering-surface forming section 207a (the up-and-down direction shown in
The rubber section 561 molded by the above-mentioned mold 202 has the shape shown in
Further, a longitudinal-direction length of a section that is included the above-mentioned rubber section 561 and that is molded by the cavity 218 is larger than a longitudinal-direction length of the rubber section 561 of the restriction blade 560 that is provided on the developing device after manufacturing processes are completed (
Further, the molded rubber section 561 is furnished with the handle section 565e at a position that is on an end section in the longitudinal direction and that is adjacent to the runner section 565b. This handle section 565e is for being grasped when taking out the molded rubber section 561 from the mold 202. The handle section 565e extends from the end section in the longitudinal direction, and its extending direction intersects the longitudinal direction of the rubber section 561. Note that, in a step to be described later (step S104), the handle section 565e is also cut and removed from the rubber section 561 together with the sprue section 565a, the runner section 565b, the gate section 565c, and the surplus section 565d.
By the way, a flash is created on the rubber section 561 that is molded by injection molding, and it is caused by the following reason. That is, if a pressure at which thermoplastic elastomer is injected into the mold 202 is large, the stationary mold portion 204 and the movable mold portion 206 deform. As a result thereof, there are cases in which a gap exists in the vicinity of the cavity 218 (specifically, the boundary surface 221). The injected thermoplastic elastomer fills not only the cavity 218 but also this gap, so that a flash is created.
Here, returning to the flowchart of
Next, as shown in
Next, the adhering jig 300 that is used when making the rubber section 561 adhere to the rubber-supporting section 566 at a desired position of the rubber-supporting section 566 is prepared. As shown in
Here, a structure of the adhering jig 300 is described.
The placing table 310 holds the rubber-supporting section 566 that is fitted into and is placed in a depressed section 311, as shown in
The revolving member 320 is a member that can revolve forward and backward while positioning and holding the rubber section 561 with a depressed section 321. As shown in
As mentioned above, sucking the rubber section 561 enables the rubber section 561 to be held by the revolving member 320 without falling, and positioning of the rubber section 561 with respect to the revolving member 320 is maintained. Note that, the revolving member 320 according to this embodiment is configured such that, in a state in which the rubber section 561 is held by the depressed section 321, the flash 564 is not in contact with the depressed section 321 while a section, of the front surface 562b, that is located on the side close to the abutting surface 562a is in contact with the depressed section 321.
Further, the revolving member 320 is connected to and is supported by the placing table 310 with a not-shown mechanism, in a state in which the revolving member 320 can revolve. Since the rubber section 561 is sucked when the revolving member 320 revolves, the rubber section 561 is held with respect to the revolving member 320 and its positioning is maintained when the revolving member 320 revolves.
With respect to the adhering jig 300 having the above-mentioned configuration, the rubber section 561 and the rubber-supporting section 566 are held in the following manner. That is, the rubber-supporting section 566 to which the double-sided adhesive tape 568 is applied is held by moving the rubber-supporting section 566 toward the depressed section 311 from above the placing table 310 in the up-and-down direction shown in
Next, the revolving member 320 that holds the rubber section 561 is relatively moved closer to the placing table 310 that holds the rubber-supporting section 566 such that the adhering surface 563a of the rubber section 561 comes in contact with the rubber-supporting section 566, and the adhering surface 563a and the rubber-supporting section 566 adhere to each other (step S110).
Specifically, the adhering surface 563a and the rubber-supporting section 566 adhere to each other in the following manner. That is, when gradually revolving the revolving member 320 that holds the rubber section 561 at the position shown in
When the rubber section 561 and the rubber-supporting section 566 adhere to each other, the revolving member 320 located at the second position is revolved until it reaches the first position after suction with the vacuum pump is finished. Due to finishing of the suction, the rubber section 561 is not held by the revolving member 320. Therefore, as shown in
As mentioned above, in the restriction blade 560 according to this embodiment, the flash 564 of the layer-thickness restriction member (the rubber section 561) is located on the side close to the non-abutting surface (the adhering surface 563a) that is located on the opposite side from the abutting surface 562a in the thickness direction of the rubber section 561. As a result thereof, a layer thickness of toner borne by the developing roller 510 is restricted evenly. This is described hereinbelow in greater detail.
As mentioned above, it is desirable that a layer thickness of toner restricted by the rubber section 561 be even. The reason is because, if a layer thickness of toner is uneven, there are cases in which, for example, streaks, etc. appear in a toner image developed by the developing roller 510, and the quality of the toner image deteriorates.
By the way, the rubber section 561 is a molded article, and, for example, there are cases in which a flash is created on the rubber section 561 in the above-mentioned injection molding. It can be considered to remove the created flash, but there are cases in which the flash is not removed in view of simplifying processes for manufacturing the rubber section 561. However, if the flash is not removed, when the flash is located close to the developing roller 510, there is a possibility in which the rubber section 561 restricts unevenly a layer thickness of toner borne by the developing roller 510.
This is described more specifically with respect to
In this case, if the flash 564 is located on the side close to the abutting surface 562a in the thickness direction of the rubber section 561 (for example, the flash 564 is located on the abutting surface 562a, or the flash 564 is located, on the front surface 562b, on the side close to the abutting surface 562a), the flash 564 becomes an obstruction to movement of toner when bringing toner into the gap A. Therefore, the amount of brought-in toner is likely to be uneven in the axial direction of the developing roller 510. If the amount of brought-in toner is uneven, a layer thickness of toner that is restricted by the rubber section 561 at the abutting position also becomes uneven.
On the other hand, if, as mentioned in this embodiment shown in
Besides, as mentioned above, a method for manufacturing the restriction blade 560 according to the first embodiment includes, as shown in
As mentioned above, as a method for manufacturing the restriction blade 560, there is known a method for obtaining the restriction blade 560 in which the rubber section 561 and the rubber-supporting section 566 are separately molded or formed in any other way and the adhering surface 563a of the molded rubber section 561 and the rubber-supporting section 566 adheres to each other. And, there are cases of employing, as a method for molding the rubber section 561, a method for molding the rubber section 561 by injection molding by injecting material of the rubber section 561 (thermoplastic elastomer) into a mold that includes a first mold that includes an abutting-surface forming section for forming the abutting surface 562a, and a second mold that includes an adhering-surface forming section for forming the adhering surface 563a and that is movable relative to the first mold.
By the way, if the rubber section 561 is molded by injection molding, the flash 564 is likely to be created on a section of the boundary surface between the first mold and the second mold when molding the rubber section by injection molding. If the rubber-supporting section 566 and the adhering surface 563a, of the rubber section 561, on which the flash 564 is created adhere to each other, there are cases in which the adhering surface 563a does not adhere to the rubber-supporting section 566 properly.
This is described in detail with reference to a comparison example shown in
On the other hand, in this embodiment, in a step in which the rubber section 561 is molded by injection molding, the rubber section 561 is molded by injection molding by injecting thermoplastic elastomer of the rubber section 561 into the mold 202 wherein the stationary mold portion 204 and the movable mold portion 206 overlap such that the boundary surface 221 between the stationary mold portion 204 and the movable mold portion 206 is located between these two molds in a direction from the abutting-surface forming section 205a toward the adhering-surface forming section 207a (the up-and-down direction shown in
In such a case, even if the flash 564 is created on the section of the boundary surface 221 when molding by injection molding, the flash 564 is located away from the adhering surface 563a in the thickness direction. Therefore, when the adhering surface 563a and the rubber-supporting section 566 adhere to each other, the flash 564 is unlikely to contact the rubber-supporting section 566. Accordingly, the adhering surface 563a properly adheres to the rubber-supporting section 566. This improves the precision of the restriction blade 560 that is manufactured.
Though the image forming apparatus, etc. according to the invention is described above based on the first embodiment, the above-mentioned embodiment of the invention is provided for facilitating the understanding of the invention, and is not to be interpreted as limiting the invention. As a matter of course, the invention can be altered and improved without departing from the gist thereof and the invention includes equivalents thereof.
Note that, in the above-mentioned first embodiment, a photoconductor that is an image bearing body is described with a structure in which a photoconductive layer is provided on an outer peripheral surface of a cylindrical conductive base, but the invention is not limited thereto. For example, a so-called photoconductive belt structured by providing a photoconductive layer on a surface of a belt-like conductive base may be used.
Note that, in the above-mentioned first embodiment, the rubber section 561 is molded by injection-molding, but the invention is not limited thereto. For example, the rubber section 561 may be molded by extrusion molding, centrifugal forming, or the like.
However, if the rubber section 561 is molded by injection molding, flashes are likely to be created on the rubber section 561 that is molded by injection molding. Therefore, an effect generated by positioning the flash 564 on the side close to the adhering surface 563a in the thickness direction, that is, an effect that a layer thickness of toner borne by the developing roller 510 is restricted evenly, is achieved more effectively. Accordingly, the above-mentioned first embodiment is more preferable.
Further, in the above-mentioned first embodiment, as shown in
However, if the flash 564 includes the flash 564b in addition to the flash 564c, the flash 564 is located more unevenly in the thickness direction than in the case in which the flash 564 includes only the flash 564c. This increases the possibility to make a layer thickness of toner uneven in the axial direction of the developing roller 510. Therefore, an effect generated by positioning the flash 564 on the side close to the adhering surface 563a in the thickness direction, that is, an effect that a layer thickness of toner borne by the developing roller 510 is restricted evenly, is achieved more effectively. Accordingly, the above-mentioned first embodiment is more preferable.
Further, in the above-mentioned first embodiment, as shown in
Further, in the above-mentioned first embodiment, as shown in
However, if the base 564a of the flash 564 is located on the edge of the end surface 562d, when the length h1 of the long-side section 562 in the thickness direction is configured larger than the length h2 of the short-side section 563 in the thickness direction, it is possible to position the flash 564 on the side close to the adhering surface 563a in the thickness direction, even in a simple configuration. Accordingly, the above-mentioned first embodiment is more preferable.
Further, in the above-mentioned first embodiment, the ten-point average height of irregularities Rz of the abutting surface 562a is smaller than the ten-point average height of irregularities Rz of the adhering surface 563a, but the invention is not limited thereto. For example, the ten-point average height of irregularities Rz of the abutting surface 562a may be larger than the ten-point average height of irregularities Rz of the adhering surface 563a.
However, if the ten-point average height of irregularities Rz of the abutting surface 562a is smaller than the ten-point average height of irregularities Rz of the adhering surface 563a, projections and depressions of the abutting surface 562a become smaller. As a result thereof, a layer thickness of toner borne by the developing roller 510 is restricted more evenly. Accordingly, the above-mentioned first embodiment is more preferable.
Further, in the above-mentioned first embodiment, as shown in
However, if the radius of curvature of the curve R1 is smaller than the radius of curvature of the curve R2, the edge of the abutting surface 562a on which the curve R1 is formed can be sharpened. In such a case, the edge of the abutting surface 562a can more easily divide toner that has reached the edge into a flow that moves the toner to the gap A and a flow that moves the toner to any place other than the gap A. Therefore, toner is effectively brought into the gap A. Accordingly, the above-mentioned first embodiment is more preferable.
Further, in the above-mentioned first embodiment, the rubber section 561 is made of thermoplastic elastomer, but the invention is not limited thereto. For example, the rubber section 561 may be made of thermosetting polyurethane.
However, if the rubber section 561 is made of thermoplastic elastomer, the rubber section 561 is easy to be molded by injection molding. Here, in the case of injection molding, the rubber section 561 can be molded such that a thickness of the rubber section 561 (a length in the thickness direction between the abutting surface 562a and the adhering surface 563a) is accurate. Therefore, if the rubber section 561 is made of thermoplastic elastomer, the rubber section 561 with great accuracy of thickness can be molded. Accordingly, the above-mentioned first embodiment is more preferable.
Further, in the above-mentioned first embodiment, the developer-bearing body is a developer-bearing roller (the developing roller 510) that is rotatable about its central axis, and the longitudinal direction of the rubber section 561 is along the axial direction of the developing roller 510. In addition, the base 564a of the flash 564 is located between the abutting surface 562a and the adhering surface 563a in the thickness direction, and the flash 564 includes the flash 564b whose edge is located on the side close to the abutting surface 562a with respect to the base 564a in the thickness direction, and the flash 564c whose edge is located on the side close to the adhering surface 563a with respect to the base 564a in the thickness direction. And, as shown in
If the flash 564 includes the flash 564b and the flash 564c as mentioned above, the possibility to make a layer thickness of toner uneven in the axial direction of the developing roller 510 will increase. If the flash 564 is located from the longitudinal-direction one end to the longitudinal-direction other end, it is likely to make a layer thickness of toner more uneven in the axial direction of the developing roller 510. In such a case, an effect generated by positioning the flash 564 on the side close to the adhering surface 563a in the thickness direction, that is, an effect that layer thickness of toner borne by the developing roller 510 is restricted evenly, can be achieved more effectively. Accordingly, the above-mentioned first embodiment is more preferable.
Further, in the above-mentioned first embodiment, as shown in
If some of the flashes 564 are in contact with the rubber-supporting section 566, there is a possibility in which a part of the adhering surface 563a does not adhere to the rubber-supporting section 566 when making the rubber-supporting section 566 and the adhering surface 563a adhere to each other; for example, this is caused by contact of the flash 564 with the rubber-supporting section 566 such that the flash 564 creates a gap between the adhering surface 563a and the rubber-supporting section 566. In such a case, there is a high possibility in which the rubber section 561 is inappropriately supported by the rubber-supporting section 566, so that there is a possibility in which the rubber section 561 improperly abuts against the developing roller 510. On the other hand, if none of the flashes 564 is in contact with the rubber-supporting section 566, the adhering surface 563a properly adheres to the rubber-supporting section 566. As a result thereof, the rubber section 561 is appropriately supported by the rubber-supporting section 566. Accordingly, the above-mentioned first embodiment is more preferable.
Further, in the above-mentioned first embodiment, as shown in
Further, in the above-mentioned first embodiment, as shown in
As mentioned above, the restriction blade 560 restricts a layer thickness of toner borne by the developing roller 510. If the flash of the rubber section 561 that is molded by injection molding is located on the side close to the abutting surface 562a in the thickness direction, there is a possibility in which a layer thickness of toner is restricted unevenly. On the other hand, if the depth of the stationary-mold recess 205 is larger than the depth of the movable-mold recess 207, the flash 564 that is created between the stationary-mold recess 205 and the movable-mold recess 207 in injection molding is located on the side close to the adhering surface 563a among the abutting surface 562a and the adhering surface 563a in the thickness direction. Therefore, this enables to prevent a layer thickness of toner borne by the developing roller 510 from being restricted unevenly.
Further, in the above-mentioned first embodiment, as shown in
There are cases in which the stationary mold portion 204 and the movable mold portion 206 overlap with their positions relative to each other being shifted when the mold 202 is closed. In such a case, if the width of the stationary-mold recess 205 in the transverse direction is the same as the width of the movable-mold recess 207 in the transverse direction, when the stationary mold portion 204 and the movable mold portion 206 overlap with their relative positions being shifted, a position at which the flash is created in injection molding is likely to vary (more specifically, the flash is positioned on the long-side section 562, or on the short-side section 563). If the position at which the flash is created is likely to vary, it is necessary to design the rubber section 561 giving consideration to the variation, and there is a possibility that limits in terms of designing increase excessively. On the other hand, if the width of the stationary-mold recess 205 in the transverse direction is larger than the width of the movable-mold recess 207 in the transverse direction, even when the stationary mold portion 204 and the movable mold portion 206 overlap with their positions relative to each other being shifted, position at which the flash 564 is created does not vary (more specifically, the flash is located on only the long-side section 562). Accordingly, the above-mentioned first embodiment is more preferable.
Further, in the above-mentioned first embodiment, as shown in
However, if the shape of the rubber section 561 is adjusted by cutting the cutting section 565f of the rubber section 561 that is molded by injection molding, the flash is not positioned in the transverse direction of the rubber section 561. Therefore, the adhering surface 563a of the rubber section 561 and the rubber-supporting section 566 can adhere to each other more properly. Accordingly, the above-mentioned first embodiment is more preferable.
Further, in the above-mentioned first embodiment, as shown in
However, if the adhering surface 563a and the rubber-supporting section 566 adhere to each other such that the flash 564 of the rubber section 561 that is molded by injection molding is not in contact with the rubber-supporting section 566, the adhering surface 563a and the rubber-supporting section 566 can adhere to each other more properly. Accordingly, the above-mentioned first embodiment is more preferable.
Further, in the above-mentioned first embodiment, as shown in
If the revolving member 320 holds the rubber section 561 such that a part of the flash 564 is in contact with the revolving member 320, there are cases in which the flash 564 is sandwiched between the rubber section 561 and the revolving member 320 when the rubber section 561 is held by the revolving member 320. In such a case, the rubber section 561 is not positioned precisely with respect to the revolving member 320. On the other hand, if the rubber section 561 is held by the revolving member 320 such that the flash 564 of the rubber section 561 that is molded by injection molding is not in contact with the revolving member 320, the flash 564 is not sandwiched between the rubber section 561 and the revolving member 320. Therefore, the rubber section 561 is properly positioned with respect to the revolving member 320. Accordingly, the above-mentioned first embodiment is more preferable.
In this section, other embodiments of a restriction blade (a restriction blade according to the second embodiment) are described. Note that the restriction blade is provided on the developing device included in the image forming apparatus, and restricts a layer thickness of toner borne by the developing roller by abutting against the developing roller. The image forming apparatus and the developing device are not described in this section since these apparatus and device are the approximately same as those described in the first embodiment.
A restriction blade 1560 has a function as a charging blade that is for charging toner T borne by the developing roller 510, and also has a function to restrict a layer thickness of the toner T. The restriction blade 1560 includes a charging member 1562 and a supporting member 1564, as shown in
The charging member 1562 is for electrically charging toner T borne on the developing roller 510 by providing electrical charges to the toner T while abutting against the developing roller 510. In this embodiment, the toner T is negatively charged as a result of being rubbed with the charging member 1562 and receiving electrons when the toner T passes through a position at which the charging member 1562 abuts against the developing roller 510. The toner T is used for development of a latent image formed on the photoconductor 20 while being negatively charged. In short, the charging member 1562 according to this embodiment serves to negatively charge the toner T.
The charging member 1562 is a member made of thermoplastic elastomer that is located on a side, of the triboelectric series, closer to a polarity (that is, positive polarity) that is opposite from a polarity for charging toner than urethane rubber. Note that material of the charging member 1562 will be described in detail later.
Further, as shown in
Note that centrifugal forming, extrusion molding, injection molding, etc. are exemplified as a method for molding the charging member 1562 that has the above-mentioned cross-sectional shape, and that all of these methods can be used without limitation. Since the charging member 1562 is made of thermoplastic elastomer in this embodiment, it is possible to mold accurately and easily the charging member 1562 having a desired shape if injection molding is selected among the above-mentioned methods.
The supporting member 1564 consists of the thin plate 1564a and a thin-plate supporting section 1564b. At a lateral-direction one end section 1564d (that is, an end section on a side close to the thin plate 1564a) of the supporting member 1564, the charging member 1562 is supported. The thin plate 1564a is a metal member that is made of phosphor bronze, stainless steel, etc. and that has a spring-like characteristic. Urging force of the thin plate 1564a makes the charging member 1562 that is supported by the thin plate 1564a abut against the developing roller 510. The thin-plate supporting section 1564b is a metal plate that is arranged on a lateral-direction other end section 1564e of the supporting member 1564, and is attached to the thin plate 1564a while supporting an end, of the thin plate 1564a, opposite from the end that supports the charging member 1562. Note that material of the thin plate 1564a is not limited to the above-mentioned metal, and polymeric materials, such as plastic, may be used as other material. Further, in this embodiment, the charging member 1562 adheres to and is fixed on the thin plate 1564a with a double-sided adhesive tape, etc., but the invention is not limited thereto. For example, the charging member 1562 may also be molded by solidification after injecting molten thermoplastic elastomer into a mold into which the thin plate 1564a is entered.
The restriction blade 1560 is attached to a not-shown holder with the longitudinal-direction both end section 1564c of thin-plate supporting section 1564b being supported by the holder.
Polymeric materials, such as urethane rubber and thermoplastic elastomer, are used for material of the charging member 1562. In this section, definitions of urethane rubber and thermoplastic elastomer in this embodiment are described.
Polymeric materials include an elastic body which has rubber elasticity (elastomer in a broad sense) and an inelastic body which does not have rubber elasticity (plastomer). The elastic body is classified into rubber and thermoplastic elastomer based on behavior of the material under heating, and the inelastic body is classified into plastic and thermosetting resin. In this embodiment, among the above-mentioned elastic bodies, an elastic body that is solidified by heating from its liquid state (that is, an elastic body showing thermosetting property) is defined as rubber, and an elastic body that is liquefied by heating from its solid state (that is, an elastic body showing thermoplasticity) is defined as thermoplastic elastomer. Besides, urethane rubber is defined as material that belongs to the above-mentioned rubber and is made of polyurethane resin.
Thermoplastic elastomer is easy to be processed because of its thermoplasticity. If this material is used as material of the charging member 1562, the charging member 1562 that is accurately molded in a desired shape can be obtained. If thermoplastic elastomer is used as material of the charging member 1562, the accuracy of attaching when attaching the charging member 1562 becomes higher than the cases in which the urethane rubber is used. As a result thereof, it is possible to make the charging member 1562 abut against the developing roller 510 more properly.
However, while thermoplastic elastomer has the above-mentioned advantages, thermoplastic elastomer is inferior to the urethane rubber in terms of wear resistance, etc. . . . Therefore, if the charging member 1562 made of thermoplastic elastomer is used, an abutting pressure at which the charging member 1562 abuts against the developing roller 510 is as difficult to increase as when using the charging member 1562 made of urethane rubber. This makes it difficult to appropriately charge the toner T, so that there are cases in which the quality of an image that is finally formed on a medium deteriorates.
Therefore, in this embodiment, thermoplastic elastomer that can solve the above-mentioned problem and is appropriate to material of the charging member 1562 is used. Here, thermoplastic elastomer according to this embodiment is described with reference to
Thermoplastic elastomer consists of a soft segment that shows remarkable rubber elasticity and a hard segment that is a phase that constrains molecules. The ether-based elastomers Ea1, Ea2, Ea3 are elastomers that include polyether as the soft segment. On the other hand, the ester-based elastomers Eb1, Eb2, Eb3 are elastomers that include polyester as the soft segment. In developing device according to this embodiment, the charging member 1562 made of the ether-based elastomer Ea1 among the thermoplastic elastomers is provided.
If the thermoplastic elastomer Ea1 is used for material of the charging member 1562, the charging member 1562 can be accurately molded in a desired shape as mentioned above. Therefore, it is possible to obtain a charging member 1562 that has higher accuracy of attaching than the cases in which any of urethane rubber U1, U2, U3, U4 is used.
Further, the ether-based elastomer Ea1 is located closer to positive polarity than the urethane rubbers U1, U2, U3, U4 in the triboelectric series, as shown in
Further, in this embodiment, the ether-based elastomer Ea1 is used as material of the charging member 1562, but the invention is not limited thereto. For example, the ester-based elastomer Eb1 may be used. However, comparing ether-based elastomer (for example, the ether-based elastomer Ea1 in
Further, in this embodiment, the charging member 1562 is made of thermoplastic elastomer that negatively charges toner T and that is located closer to positive polarity than urethane rubber in the triboelectric series, but the invention is not limited thereto. For example, by using developer that is located closer to positive polarity than urethane rubber and thermoplastic elastomer in the triboelectric series, the charging member 1562 may positively charge this developer (that is, in the image forming apparatus, the developer is used for development of a latent image while being positively charged). In such a case, the charging member 1562 made of thermoplastic elastomer that is located closer to negative polarity than urethane rubber in the triboelectric series (for example, the ether-based elastomer Ea3 or the ester-based elastomer Eb3 shown in
Next, an embodiment of an image forming system that is an example of the embodiments according to the invention is described with reference to the drawings.
In this embodiment, the computer 702 is accommodated in a mini-tower type enclosure, but the invention is not limited thereto. Regarding the display device 704, a CRT (Cathode Ray Tube), a plasma display, a liquid crystal display device, and the like are generally used, but the invention is not limited thereto. Regarding the printer 10, the printer described above is used. A keyboard 708A and a mouse 708B are used as the input devices 708 in this embodiment, but the invention is not limited thereto. A flexible disk drive device 710A and a CD-ROM drive device 710B are used as the reading devices 710 in this embodiment, but the invention is not limited thereto. For example, a MO (a Magneto Optical) disk drive apparatus, a DVD (a Digital Versatile Disk) and the like may also be used.
Note that, in the above description, an example of the image forming system having the configuration in which the printer 10 is connected to the computer 702, the display device 704, the input devices 708, and the reading devices 710 is described. However, the invention is not limited thereto. For example, the image forming system may be composed of the computer 702 and the printer 10, or the image forming system may be constructed without any of the display device 704, the input devices 708 and the reading devices 710.
Further, for example, the printer 10 may have some of functions or mechanisms of the computer 702, the display device 704, the input devices 708, and the reading devices 710. As an example, the printer 10 may be configured having an image processing section for performing image processing, a displaying section for performing various types of displays, and a recording-media attach/detach section to and from which a recording medium storing image data captured by a digital camera or the like is inserted and taken out.
As an overall system, the image forming system that is achieved as mentioned above becomes superior to prior systems.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2006-124062 | Apr 2006 | JP | national |
| 2006-124063 | Apr 2006 | JP | national |
